For those that have actually fired a 'high-end' AR15 (i.e. Colt, Noveske, etc.), do different components like the heavier M16 style BCG or heavier H-stamped buffer make the rifle 'feel' different when fired than say, entry level rifles without those parts?

That said you're better off with a few better parts on a no-name AR than something "mil spec" with premium branding.

I was rather disappointed shooting a friend's Colt which was far less accurate than I was. I really liked my Armalite Action Master with NM trigger and float tube especially running NM iron sights. I'm going to be even happier when I finish my generic machine shop project that has a Geissele trigger I'll drop in once done.

The relevant difference was closer to "as issued" and "space gun" respectively not the name stamped on the side.

As a Californian, a more recognizable name means you're more likely to end up on the assault weapon list. That could be good (once you have a registered assault weapon you don't need a stupid bullet button or grip abomination) or bad (you need to register the lower if you keep it in state). Banned by name guns are also a problem when you move between states (I left my M15 marked Armalite in a Washington state storage facility from whence it was stolen) and California isn't the only place with silly rules.